This application claims the priority of German Patent Document 100 07 151.1, filed in Germany, Feb. 17, 2000, the disclosures of which is expressly incorporated by reference herein.
The invention relates to a liquid cooled cross flow cylinder head for internal combustion engines with cylinders arranged in series, wherein the cylinder head with integrated control housing comprises a coolant chamber, defined by side walls, between a cylinder head bottom and a control housing-sided cover wall. The screw pipes, which penetrate the coolant chamber and the cover wall starting from the cylinder head bottom, as well as oil outlet channels and shaft tubes, arranged approximately in the center of the cylinder, are provided for spark plugs or injection nozzles. Furthermore, the coolant chamber is divided by cross walls between diametrical screw pipes.
Such a cylinder head is known, for example, from the German Patent Document No. DE 38 38 953 C2, where the cross walls, which are located between the diametrical screw pipes and penetrate the coolant chamber so as to follow its height up to the planar cover wall and further to the cross walls in the connecting planes of shaft tubes, adjoining at right angles, are provided in front of the longitudinal walls, which end the shaft tubes and which for a cross flow of the cylinder head serve to divert the coolant in the direction of the shaft tubes and the adjacent areas of the cylinder head bottom, which is provided with additional guide ribs.
The drawback with this known cylinder head is the complicated casting structure and the very large coolant chamber design.
The invention is based on the problem of designing this class of cylinder head by simple casting technology in such a manner that there is high rigidity and the coolant is guided specifically at least in cross flow.
This problem is solved according to the invention in that the cover wall exhibits a cavity between diametrical screw pipes and shaft tubes, which adjoin at right angles, which cavity is connected to the cylinder head bottom by a cross wall between the diametrical screw pipes. The cavity""s wall segments that ascend from the cross wall in the direction of the cover wall serve as the flow guide surfaces.
With the invention, an especially rigid cylinder head is achieved in an advantageous manner in that the cavity, connected by cross walls to the cylinder head bottom, constitutes a simpler casting design. In another advantageous manner, better venting of the cylinder head is achieved with the omission of special guide ribs for influencing the flow.
According to the invention, the cavities for a cylinder head can be designed as a separate component. However, in a further development of the invention they are preferably cast as one piece so that, when viewed from the top, a cavity expands, starting from each screw pipe, in the direction of a connecting plane of the shaft tubes, which adjoin at right angles, and serves to direct the flow in the direction of the shaft tubes.
The aforementioned measures preferably support coolant cross flow in the cylinder head. In another design of the invention a longitudinal flow can also be achieved in that the cross wall between the cylinder head bottom and the cavity exhibits a flow passage in the longitudinal direction of the cylinder head. In this manner additional oncoming flow in the vicinity of the bottom of the shaft tubes can be achieved.
To drain the lubricating oil, which flows from the control housing of the cylinder head into a cavity, another proposal provides that the cavity is connected by a separate channel to the oil outlet channel. In another design an inlet opening of the separate channel is arranged in the cavity in accordance with the installation position of the cylinder head. Thus, the circulating quantity of lubricating oil is kept low; and unnecessary heating is avoided.
Finally the invention achieves an additional reinforcement of the cylinder head in that the cavity exhibits along its opening rim a reinforcement leg, which projects beyond the cover wall. This arrangement achieves by an advantageous casting method that reinforcement legs run transversely to the longitudinally positioned cylinder head between the screw pipes. According to the inventive shape of the cavity, the reinforcement legs extend in the shape of a V beyond the cylinder head and thus additionally reinforce it both in the cross and the longitudinal direction.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.